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<head>
    <meta charset="UTF-8">
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    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        let arr = [
            ['a',1],
            ['b',2],
            ['c',3],
            ['d',4],
        ]
        let s = new Map(arr);
        // console.log(s.size);//length
        // s.clear()//清空
        // console.log(s);
        // s.delete('a')//删除某一项
        // console.log(s.get('b'));//获取b的值
        // console.log(s.has('d'));//是否包含d
        // s.set('e',5)//添加 设置某一值 
        // s.set('a',3).set('e',4)

        console.log(s);
    </script>
</body>
</html>